I have legacy code performing a subtraction of signed int with an unsigned int and a cast of the result to a float. It was giving expected result with Visual Studio 6 to 2013. With Visual Studio 2017 (15.6.3) the result is not the expected one.
I have simplified the code to this:
unsigned int uint = 10;
signed int sint = 9;
signed int res = sint - uint;
float fres = static_cast<float>(sint - uint);
res value is -1 with all the VS I have tested.
With VS 2013 and before, fres value is -1. With VS 2017, fres value is 4.29496730e+09, that is to say UINT_MAX.
I have found here that the fres result in VS 2017 is the one conforming to the C++11 standard (if I correctly understand).
VS 2017 compiler is not issuing any warning on this.
How can I detect all the occurrence of such a bad subtraction in my code base?
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